In a recent mobile phone system, subscribers to mobile phone services have been dramatically increasing, and there have been cases where mobile terminals already sold are recalled to repair the failure thereof.
For purposes including to avoid the recall of mobile terminals, 3GPP2 (3rd Generation Partnership Project 2) has been studying OTASP (Over The Air Service Provisioning) to rewrite or update software in a mobile terminal via radio (e.g. see Non Patent Document 1).
In this case, paging may be used as a technique for specifying a mobile terminal whose software is to be rewritten. In the paging technique, when there is an incoming call or data to a mobile terminal, it is required to inform the mobile terminal of the call, and all mobile terminals in the location registration area where the mobile terminal has registered the location are informed of the call by broadcast. Accordingly, the mobile terminal recognizes the paging thereto since it is always monitoring a paging channel even in idle mode (e.g. see Non Patent Document 2).
However, it is inefficient to forward data to each of mobile terminals one by one, and therefore, techniques have been proposed in which data is broadcast to all mobile terminals whose software needs to be rewritten (e.g. see Patent Documents 1 and 2).
Patent Document 1: Japanese Patent Laid-Open No. 2001-28787 (Paragraphs 7 and 8, FIG. 1)
Patent Document 2: Japanese Patent Laid-Open No. 2003-51796 (Paragraphs 6 to 8, FIG. 1)
Non Patent Document 1: 3GPP2 Access Network Interface Interoperability Specification Release A, June, 2000
Non Patent Document 2: “W-CDMA Mobile Communications System, Chapter 4: Network Technologies, Chapter 4-3: Network control and signaling Scheme” edited by Keiji Tachikawa, published by Maruzen Co., Ltd., Jun. 25, 2001, pp 254-256